Gangs are everywhere in Hillsborough, as a recent triple-homicide in a quiet Brandon neighborhood underscored.

Authorities suspect gang ties in the killings of three men and the beating of a fourth. Friends and neighbors expressed surprise at the suggestion of gang involvement.

But Hillsborough sheriff's deputies say gangs have quietly infiltrated the suburbs as a way to keep a low profile and avoid police scrutiny.

Sheriff's officials have compiled a list of more than 4,000 people they say are involved in about 100 gangs, from the Bloods to the Draks to the Goyams.

Pinellas does not have the staff to track gang members as closely as Hillsborough, but about 250 people have been prosecuted as gang members in the past three years, said Norm Miller, an investigator with the Pinellas-Pasco State Attorney's Office. Pasco has about 250 gang members there, said Kevin Doll, a spokesman for the Pasco Sheriff's Office.

Gang members come from all races, ages and ethnic backgrounds and have been linked to crimes ranging from grand theft auto to burglary to drug dealing, authorities say.

"This is something that's been going on longer than you and I have been living," said Hillsborough sheriff's Detective Marc Wilder, 40. "People long to belong to something. We all like to belong."

Wilder has been with the sheriff's gang unit for six years, after four years working in property crimes, which first exposed him to gangs.

Wilder said the number of active gang members has more than doubled in the past six years, to about 4,300.

That could suggest a marked rise in gangs or that detectives are getting better at identifying them. Wilder thinks it could be a combination of both.

Wilder said the largest gang concentration is in Tampa's Sulphur Springs neighborhood, but they're spreading to every part of town.

Ask Wilder about a particular gang, and he'll rattle off its colors, creed and subsets. He knows their prayers. He knows their symbols. He recognizes the difference between a kid wearing baggy jeans and a backwards cap and one in a gang get-up.

The Sheriff's Office keeps a computer database of all everyone it has identified as a gang member — anyone who meets two of 12 gang criteria, including associating with known members, wearing clothing with gang symbols or reciting certain gang prayers or creeds.

Belonging to a gang isn't illegal. But a gang member convicted of a crime can face harsher punishment. A misdemeanor graffiti charge, for example, could be bumped up to a third-degree felony, Wilder said.

Authorities say 22-year-old Tony Black, one of the three men slain in the back yard of a Brandon home just after midnight Tuesday, was a self-proclaimed member of the notorious Bloods gang.

In previous brushes with the law, Black readily admitted gang participation, Wilder said. He also had Bloods tattoos and wore black-and-red bandanas and clothes.

Deputies have not said the other three men who were with Black that night were gang members. But deputies are suspicious because they were hanging out with him.

Wilder said gang members carefully choose friends who "live the same lifestyle."

Vincent Thomas, 22, who lived at the home where the attack happened, was shot to death. So was Black. Rafael G. Guadalupe, 21, was found stabbed to death. Ralph Arroyo, 21, was beaten up, survived and was interviewed by detectives.

Deputies said they've pinpointed "key players" in the murders and were questioning several people, but no one had been arrested. They said potential suspects also have gang ties and that the murders may have been preceded by illegal drug activity.

Wilder said the Bloods is one of the fastest growing gangs in Hillsborough. Originally a break-off group of Black Panthers in Chicago, the gang migrated to Los Angeles before spreading throughout the country.

Many large gangs keep detailed Web sites to instruct potential members how to join. "Kids can sit in the middle of Bloomingdale in their nice little suburb and talk to gang members in L.A.," Wilder said. "They can find out how to start a gang and do initiations and everything else."

The Sheriff's Office and Tampa police try to fight back with a collaborative interactive Web site, Tampabaygangs.com. Former Bucs star Warrick Dunn greets visitors, and Tampa residents talk about their gang concerns and give tips about reporting and reducing gang activity.

The agencies also offer tips to neighborhood groups about spotting gangs and keeping them away. They put up billboards urging people to call Tampa Bay's anonymous gang tip line (877-426-4688) with information about members or crimes.

But it's not easy.

Wilder said gangs often migrate to uncharted territory, and that often means quiet parts of town where they can break into homes with nice things and leave without being questioned, Wilder said.

Curious kids keep joining, and violent crimes continue.

So day after day, Wilder studies. He pores over pictures of gang symbols and crime evidence. He drives the streets and looks for patterns and colors in graffiti.